Cognitive accessibility (MDN Web Docs)
MDN’s guide to designing for cognitive and learning disabilities, organized around the WCAG success-criteria categories most relevant to this population: adaptability, time limits, navigation, readability, predictability, and input assistance.
License: CC BY-SA 2.5+ (Mozilla Contributors).
Key points
- Time limits: extend to at least 10× the original where a limit can’t be eliminated outright, give at least 20 seconds’ notice via a simple action before expiry, save data before a timeout so work isn’t lost, and warn about impending inactivity-driven timeouts.
- Navigation: descriptive page titles, clear headings/labels, multiple ways to find content (search, sitemap, table of contents), skip links, DOM/visual/tab order alignment, a visible focus indicator, meaningful link text, and breadcrumbs or a sitemap showing current location.
- Readability: declare the page’s language via the
langattribute; define unusual words/idioms/jargon inline or via a glossary; expand abbreviations on first use with<abbr>; write at a simple reading level (short words/sentences, active voice, present tense); offer a TL;DR summary at a lower reading level for long content; use visual aids to explain concepts. - Predictability: never trigger a context change (navigation, submission, new window) just from an element receiving focus — require an explicit activating action; keep navigation position/order consistent across every page; use consistent labeling for identical functions; follow standard web conventions rather than surprising users with unfamiliar link/visited-state colors.
- Input assistance: specific (not generic) error messages; identify incomplete/invalid fields in text, not just visually; focus on the first error, or provide a linked summary when there are several; position form instructions at the start; suggest corrections when an error is detected; let customers review, confirm, and correct before final submission; provide reversibility or an amendment window for legal/financial transactions.
- General: minimize distractions (unnecessary ads/content), use familiar UI patterns, and divide complex processes into logical steps with progress indicators.